Connexion à une base de données avec un singleton
Bonjour. Je souhaite réaliser une classe Singleton pour pouvoir me connecter à une BDD, mais je rame un peu !
Voici l'erreur que j'obtiens à la compilation :
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| DBConnection.h: In member function `DBConnection& DBConnection::operator=(const
DBConnection&)':
DBConnection.h:20: warning: no return statement in function returning non-void
DBConnection.cpp: In constructor `DBConnection::DBConnection()':
DBConnection.cpp:9: error: `class QSqlDatabase::addDatabase' is not a type
DBConnection.cpp: At global scope:
DBConnection.cpp:34: error: ISO C++ forbids declaration of `get_db' with no type
DBConnection.cpp:34: error: prototype for `int DBConnection::get_db()' does not
match any in class `DBConnection'
DBConnection.h:12: error: candidate is: static DBConnection DBConnection::get_db
()
DBConnection.cpp:34: error: `int DBConnection::get_db()' and `static DBConnectio
n DBConnection::get_db()' cannot be overloaded
DBConnection.cpp: In member function `int DBConnection::get_db()':
DBConnection.cpp:35: error: cannot convert `QSqlDatabase' to `int' in return |
DBConnection.h
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| #ifndef DEF_DBCONNECTION
#define DEF_DBCONNECTION
#include <QSqlDatabase>
#include <iostream>
class DBConnection
{
public:
static DBConnection* Get();
static void Kill();
static DBConnection get_db();
private:
static DBConnection* m_instance;
DBConnection();
~DBConnection();
DBConnection& operator= (const DBConnection&){}
DBConnection (const DBConnection&){}
QSqlDatabase db;
bool check_con;
};
#endif |
DBConnection.cpp
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| #include "DBConnection.h"
using namespace std;
DBConnection* DBConnection::m_instance=0;
DBConnection::DBConnection()
{
db = new QSqlDatabase::addDatabase("QMYSQL");
db.setHostName("localhost");
db.setDatabaseName("bob");
db.setUserName("truc");
db.setPassword("muche");
}
DBConnection::~DBConnection(){}
DBConnection* DBConnection::Get()
{
if(m_instance==0)
{
m_instance=new DBConnection();
}
return m_instance;
}
void DBConnection::Kill()
{
delete m_instance;
m_instance=0;
}
DBConnection::get_db()
{
return db;
} |
Et le morceau de code que j'utilise pour créer ma connection :
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| DBConnection* con_DB=DBConnection::Get();
db = con_DB->get_db();
if( db.open())
{
m_TexteInformation->setText("réussi !");
}
else { m_TexteInformation->setText(":(");} |
Voilà... merci d'avance.
